Mechanism for laterally vibrating the needle of a zigzag sewing machine

ABSTRACT

A mechanism for positively jogging a needle bar gate laterally from a rotary actuator within the constricted space of a sewing machine frame. An arm extending from the needle bar gate and an arm of a lever in the machine frame which is rocked by the rotary actuator are interconnected and both arms are flexible only in one common plane to accommodate differences in the arcuate paths of motion thereof, the arms being otherwise rigid to transmit lateral jogging motion in a positive manner to the needle bar gate.

United States Patent 1191 A Tolle 1 1 Mar. 5, 1974 1 1 MECHANISM FORLATERALLY VlBRATlNG THE NEEDLE OF A ZIGZAG SEWING MACHINE [76] Inventor:Gunter Tolle, 752 Bruchal 4/ Wendclinusstr. l5, Bruchsal, Germany -22Filed: Feb. 16, 1973 2| 1 Appl. N6; 333,259

'[30] Foreign Application Priority Data May 6, 1972 Germany 2222370 52us. c1 112/158 R 51 I Int. Cl D05b 3/02 [58] Field o Search.. .l l2/65,66, 73, 158 R, 158 B, 112/158 c [56] References Cited UNITED STATESPATENTS 2,618,231 11/1952 Turner 112/158 R X 4/1959 Amman 112/158 X10/1962 Hirk. 112/1511 X Primary E aminerWerner HQ Schroeder Attorney,Agent, or FirmMarshall .1. Breen; Chester A. Williams, Jr.; Robert Smith[57] ABSTRACT A mechanism for positively jogging a needle bar gatelaterally from a rotary actuator within the constricted space of asewing machine frame. An arm extending from the needle bar gate and anarm of a lever in the machine frame which is rocked by the rotaryactuator are interconnected and both arms are flexible only in onecommon plane to accommodate differences in the arcuate paths of motionthereof, the arms being otherwise rigid to transmit lateral joggingmotion in a positive manner to the needle bar gate.

2 Claims, 5 Drawing Figures PAIENTED 51974 SHEEI 1 0F 2 1 MECHANISM FORLATERALLY VIBRATING THE NEEDLE OF A ZIGZAG SEWING MACHINE BACKGROUND OFTHE INVENTION The problem of imparting lateral jogging motion to aneedle bar gate in a sewing machine is facilitated when ample space isprovided because differences in arcuate paths of motion as betweeninterconnected parts may then be minimized. Solution to problem is alsofacilitated in sewing machines driven at moderate or slow speeds whereinthe needle bar gate may be positively driven in only one direction andspring biased in the other direction.

The present invention provides a mechanism for positively jogging aneedle bar gate in both directions .utilizing only a minimum amount ofspace within the sewing machine frame. Because the parts of themechanlsm are compactly arranged and positively interconnected,deflections and tolerance accumulations are minimized and an accuratehigh speed needle jogging mechanism results; A'- problem arises with thecompact arrangement of positively interconnected parts in thatdifferences in the arcuate paths of motion of the various interconnectedparts must be reconciled.

- 'BRIEFSUMMARY .OF THE INVENTION DEVSCRIFTION OF THE, DRAWINGS With theabove and other objectsand advantages in view this invention isillustrated in a preferred embodiment in the accompanying drawings inwhich:

FIG. 1 represents a side elevational view partly in verticalcross-section of'a sewing machine having this invention applied thereto,2

FIG. 2 is a disassembled perspective view of the needle bar vibratingmechanism of this invention FIG. 3 is a cross-sectional view takensubstantially along line 3-3 of FIG. 1 showing the assembled needle barvibrating mechanism of this invention,

FIG.'4 is a cross-sectional'view taken substantially along line 4-4 ofFIG. 1 showing the assembled needle bar vibrating mechanism of thisinvention, and

FIG. 5 is a perspective view of the assembled flexible arms of themechanism of this invention.

FIG. 1 illustrates a sewing machine to which the needle joggingmechanism of this invention may be applied. The sewing machineillustrated in FIG. 1 is a buttonhole sewing machine including astationary frame portion 11 in which a needle carrying bar 12 is sup-The needle bar 12 is endwise reciprocable in a needle bar gate 20 whichis formed with conical sockets 21 engageable by trunnion pins 22 securedin the stationary frame portion 11. The trunnion pins define a pivotalaxis A-A about which the needle bar gate can swing to impart lateralvibratory movement to the needle bar for forming zigzag stitches whichare necessary to produce a buttonhole.

The needle bar is reciprocated endwise in the needle bar gate by meansof a lateral stud extending from the needle bar and embraced by a drivelink 31 which also embraces a crank pin 32 secured on a main shaft 33 inthe stationary frame portion 11. The drive link 31 may be bifurcated asat 34 to embrace a stabilizing bracket 35 to prevent interferencebetween the swinging movement of the needle bar gate and the endwisereciprocatory movements imparted to the needle bar by the drive link 31.

For deriving the lateral jogging movements of the needle bar, a sprocketon the main shaft meshes with a timing belt 41 which extends intodriving relation with a sprocket 42 carried on a countershaft 43journaled in "the stationary frame portion 11. It is a crank'44 on thecountershaft' 43 which in partaking of rotary movement gives rise to thelateral jogging motion-imparted to the needle bar gate. The 'co -pendingapplication Ser. No; 333,257 filed Feb. I6, 1973 which is incorporatedherein by reference may be referredto for a detailed description of amechanism for varying the positionand amplitude of movement of the crank1 that the mechanism of this invention for transmitting lateral. joggingmovements to the needle'bar is adapted to the compact space requirementsof a buttonhole sewing machine with high speed operatingcharacteristics.

Referring to FIGS. 2 and 3, the needle bar gate 20 is formed with aprojection carrying a pivot pin 51 on which a bracket 52 isjournaleduThe angular relation of the bracket 52 to the needle bar gate20 is influenced by a headed screw 53 which passes through a clearanceaperture 54 in the bracket and is threaded into the needle bar gate, anda set screw 55 threaded in the bracket The freeextremity of the leafspring 57 is embraced bya conical split block 58 on which a sphericalball 59 ofa universal connection 60 is'forced by a nut 61 which engagesthreads 62 formed on the split block.

Secured as by a rivet to a flange 71 extending from a spherical socket72 which embraces the spherical ball 59 and forms partof the universalconnection 60, is a lever arm 73 preferably provided by a flat leafspring.

The lever arm 73 forms one arm of a bell crank lever indicated generallyas 74. Secured to each side of the lever arm 73 is an apertured spacerblock 75 and a rigid lever arm 76. Each of the lever arms 76 is formedwith a fulcrum aperture 77 and also formed with a substantially radialslot 78. A bushing 79 arranged in the fulcrum aperture 77 accommodates afulcrum pin 80 threaded into a boss 81 of the stationary frame portion11. Rivets 82 serve to sustain the lever arms 76 and spacer block 75 inassembled relation with respect to the lever arm 73.

A drive link 90 embracing the crank pin 44 also embraces a headed pivotpin 91 which may be secured in selected positions along the radial slots78 of the rigid lever arms 76 by a clamp nut 92 threaded on the pivotpin 91 preferably with a washer-sleeve 93 interposed between the pivotpin 91 and each of the lever arms 76. By adjustment of the pivot pin 91along the slots 78 the amplitude of zigzag movements derived from thecrank pin 44 may be changed. By adjustment of the headed screw 53 andthe set screw 55, the position of the needlebar gate may be adjustedabout the pivotal axis A-A to effect a positional adjustment of theneedle bar gate without influence upon the amplitude of zigzag movement.

As indicated in FIGS. 1 and 2, the flat leaf spring 57 forms a part ofan arm projecting from the needle bar gate in a plane substantiallyperpendicular to the pivotal axis A-A of the needle bar gate. Theextremity of the flat leaf spring 57 to which the universal connection60 is secured, therefore, will move in'an'arcuate path indicated at 8-8in FIG. 3. The lever arm'73 must be capable of movement laterallyinorder to accommodate the arcuate path 8-8 of the arm 57. Suchaccommodation is provided by theflexibility of the lever arm 73resulting from the construction of the lever arm 73 v as a leaf spring.

As indicated in FIG. 4, the lever arm 73 since it turns about thefulcrum pin 80 providing a fulcrum axis C-C for the bell crank lever 74,will move in an arcuate path indicated as D-D. The arm 57 mustbe capableof movement out of its usual plane in order to accommodate this arcuatepath D-D of the lever arm 73. Such accommodation is provided as a resultof the construction of the arm 57 as a leaf spring, As shown in FIG. 5,the arm S7'and the lever arm 73 are each formed of flat leaf springmaterial arranged substantially perpendicular to each other so as eachto be flexible only in a common plane X-X. [n all other directions thearm 57 and the lever arm 73 will be rigid'and, therefore, able totransmit forces in a positive manner. As shown in FIG. 3, the plane X-Xis parallel to both the pivotal axis A-A of the needle bar gate and tothe fulcrum axis C-C of the bell crank lever 74. By this arrangement themotion derived from the crank pin 44 may be transmitted into positivelateral jogging movements of the needle bar gate in each direction.Because of the flexibility of the arms 57 and 73 in the common planeX-X, the angular paths of motion of the interconnected elements of themechanism for transmitting the needle jogging motion can beaccommodated.

The accommodation of different paths of motion of the interconnectedelements of the needle jogging mechanism is accomplished in sosatisfactory a manner by this invention that extremely small radii ofthe arms 57 and 73 with consequent large angular movements thereof maybe tolerated successfully with the result that the mechanism of thisinvention may be accommodated in very compact space. Extremely narrowbuttonhole machines which permit closer spacing so that adjacentbuttonholes may be simultaneously stitched close together may be madeusing this invention.

Having set forth the nature of this invention, what is claimed hereinis: v

1. A sewing machine having a needle carrying bar endwise reciprocable ina gate pivotally supported on an axis fixed in the sewing machine frame,and a rotary actuator journaled in said frame for vibrating said needlebar gate laterally, mechanism operated by said rotary actuator forshifting said needle bar gate positively in each direction of lateralvibration characterized by an arm projecting from said needle bar gate,a lever arm pivotally supported on a fulcrum axis fixed in said sewingmachine frame, said lever arm being articulated by a universalconnection to said needle bar gate arm, means in said needle bar gatearm and in said lever arm 'providing'for flexibility of each of saidarms only in a common plane which is substantially parallel to thepivotal axis of said needle bar gate and to the fulcrum axis of saidlever arm, and a drive link operatively connecting said rotary actuatorwith said lever arms 2. A sewing machine as set forth in claim 1characterized in thatthe means in both said needle bar gate arm and saidlever arm for providing flexibility only in a common plane comprisesflat leaf springs forming at least a part of each of said arms, saidflatleaf springs being arranged in substantially mutually perpendicularrelationship. 7

1. A sewing machine having a needle carrying bar endwise reciprocable ina gate pivotally supported on an axis fixed in the sewing machine frame,and a rotary actuator journaled in said frame for vibrating said needlebar gate laterally, mechanism operated by said rotary actuator forshifting said needle bar gate positively in each direction of lateralvibration characterized by an arm projecting from said needle bar gate,a lever arm pivotally supported on a fulcrum axis fixed in said sewingmachine frame, said lever arm being articulated by a universalconnection to said needle bar gate arm, means in said needle bar gatearm and in said lever arm providing for flexibility of each of said armsonly in a common plane which is substantially parallel to the pivotalaxis of said needle bar gate and to the fulcrum axis of said lever arm,and a drive link operatively connecting said rotary actuator with saidlever arm.
 2. A sewing machine as set forth in claim 1 characterized inthat the means in both said needle bar gate arm and said lever arm forproviding flexibility only in A common plane comprises flat leaf springsforming at least a part of each of said arms, said flat leaf springsbeing arranged in substantially mutually perpendicular relationship.